The pathogenesis of Degenerative Diseases of aging such as Alzheimer's Disease (AD) and osteoarthritis (OA) involve the loss of important functional cell types. Apoptosis is a form of programmed cell death that is responsible for the elimination of many cell types during development. We have initiated studies into the role of apoptosis in age-associated processes. Previously we utilized an in situ method to demonstrate that samples from the hippocampus of AD patients show an increased incidence of apoptosis compared to age-matched controls. We have now carried out immunostaining of the sections to show that although neurons are involved, the majority of the dying cells are glial. Studies with chondrocytes have shown that several relevant signals can induce apoptosis in this cell type, including trophic factor withdrawal.